Hey there! I can't seem to find any guides online that lists the possible graphics card upgrades for the AGP 1.6GHz single processor G5 PowerMac. Does anyone know what graphics upgrades this model supports? The FX5200/5500 in it really isn't up to snuff for much. Also... is it capable of using mismatched RAM? I.e. a 1GB and 512MB stick in the slots? I have two matched pairs of 512MB for 2GB RAM but was thinking of getting more.